The problem when attempting to measure DeSean Jackson's worth has always been that the Eagles receiver is not easily quantifiable.

The uniqueness of Jackson is that he can score from almost anywhere on the field, sometimes with the game on the line, sometimes in dramatic fashion. You can't quantify that with traditional statistics like catches, yards and touchdowns.

It's likely one of the primary reasons why the Eagles and Jackson have yet to agree on a contract extension. Of course, the more this season plays out, the more it is starting to appear as if the Eagles may not want to re-up the fourth-year receiver.

Statistically, Jackson is performing in line with his career averages. But numbers tell only part of the story. Jackson, through eight games, has failed to produce the one thing that has made him so special and arguably on par with the best receivers in the game: the big play.

It's one reason why the Eagles are off to a disappointing 3-5 start.

"For myself, at times, it's frustrating because I am used to the big plays, scoring long touchdowns," Jackson said Monday night after the Eagles blew another fourth-quarter lead and lost to the Bears, 30-24. "But right now it's not really working. Defenses are not letting it happen."

Jackson's longest play - a 61-yard catch - is the Eagles' longest from scrimmage this season. But his longest touchdown was on a 31-yard screen pass four games ago at Buffalo. He has only one other score - a six-yard touchdown in the opener at St. Louis.

While placing emphasis on the distance of a touchdown may overstate its worth, for Jackson it's what separates him from many players. Of his 28 career touchdowns, 20 have covered 30 or more yards.

But it's not just the long touchdowns that are missing from Jackson's resume. It's the long ball in general.

He is on pace to finish with just eight catches for 340 yards and no touchdowns from passes thrown more than 20 yards, according to ProFootballFocus. In his first three seasons, Jackson averaged 12 receptions for 474 yards and three touchdowns on "deep" passes.

His struggles, he has said, are partly attributed to defenses increasingly playing him deep and double covered.

"I guess they try to do everything in their power to not let us run on the field and make those big plays that we have made over the years," Jackson said. "I have to find a way to make it happen and get through it."

Jackson was targeted eight times against the Bears, but not one of those passes was a deep throw. The week before against the Cowboys, not one of six passes thrown his way were more than 20 yards downfield.

Eagles coach Andy Reid was asked if quarterback Michael Vick was showing hesitancy in taking shots downfield.

"I wouldn't say he's hesitant," Reid said Monday. "He wants to make sure he has a clear look at it, and normally if you're taking a vertical shot on a deep safety, than you're going to need a little time to do that."

Even when teams have taken the long ball away from Jackson, the Eagles have found other ways to get him involved. While the passes have been shorter this season, Jackson is still not coming up with the catches. In the last three games, he's been targeted 19 times but has caught only eight for 93 yards.

At this point, it is fair to wonder if Jackson's contract situation is affecting his performance. Reid said that he did not believe it was. Jackson has admitted that he did let it affect his play last year.

He held out from the start of training this season to let the Eagles know he was unhappy with his deal but has tried to stay away from the topic since reporting. Jackson is earning approximately $600,000 in base salary this season.

Negotiations between the Eagles and Jackson's agent, Drew Rosenhaus, haven't appeared to reach a serious state. It is unclear how much Rosenhaus thinks his client is worth. The Eagles could franchise Jackson in February before letting him become a free agent. They could also try to trade him.

Or they reach an agreement.

Despite his under-the-radar play, Jackson is on pace to catch 58 passes for 1,006 yards and four touchdowns, numbers very close to his career averages of 57 catches for 1,041 yards and six touchdowns.

But the big play has been missing, not just receiving but running and returning. Jackson has three career rushing and four punt return touchdowns. He has none in either category this season and has been uninspiring returning punts. He is averaging 3.7 yards a return and had a costly muff when he danced backward on a return against the Bears.

"He's broken some, so he's going to try to make something happen, and that one didn't work," Reid said. "That was a negative play."